Vehicle Headrest

ABSTRACT

A vehicle headrest includes a main body portion having a front surface arranged to support a back of a head of a user. The main body portion includes first and second speakers which are disposed within the main body portion, and a cushion layer that is configured to surround the speakers and provide cushioning for a user&#39;s head. The cushion layer includes acoustic channels for controlling a radiation pattern of acoustic energy radiated from the speakers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14,154,924, filed Jan. 14, 2014, which is incorporated herein byreference in its entirety.

BACKGROUND

This disclosure relates to a vehicle headrest.

FIGS. 1A through 1C illustrate an example of a headrest 100 thatincorporates speakers 102. Referring to FIG. 1A, the speakers 102 areattached to a U-shaped support rod 104 and are positioned to lay in aregion that is directly behind the user's head (i.e., as opposed to thebeing located on the left and right sides of the U-shaped support rod104) and to fire outwardly, in diverging directions on either side ofthe headrest 100.

A small plastic enclosure 106 is attached to each speaker 102 forforming an acoustic enclosure. Each of those sub-assemblies then getsscrewed into a two-piece sheet metal cage 108 which is secured to theU-shaped support rod 104. FIG. 1A shows a partial assembly with a frontportion of the sheet metal cage 108 removed to view the speaker 102 andenclosures 106. FIG. 1B shows the sheet metal cage 108 fully assembledwith the front portion 110 in place. This construction can leave a gapbetween a front portion 110 of the sheet metal cage 108 and the exposedsurfaces of speakers 102 which can allow for leakage of acoustic energybetween the speakers 102 resulting in left speaker radiation from rightspeaker opening and vice versa.

A molded piece of foam cushioning is placed around that assembly, whichis subsequently covered with a cover material 112 (e.g., fabric orleather), and there are a pair of plastic covers 114 which includegrille regions 116, for covering the speakers, that are off on eitherside of the headrest 100, as shown in FIG. 1C. The plastic covers 114are secured to the sheet metal cage 108. The plastic covers 114 protectthe speakers 102 and assist in directing the radiation of acousticenergy toward the front the headrest 100. In the finished assembly, theplastic covers 114 reside on either side of the molded foam cushioningand contribute to the overall width of the headrest 100.

SUMMARY

This disclosure is based, in part, on the realization that a headrestcan be provided with cushioning member that includes acoustic channelsfor controlling a radiation pattern of acoustic energy radiated fromspeakers integrated within the headrest. Integrating acoustic channelswithin the cushioning member can eliminate the need for externallymounted structures for directing acoustic energy, which can help toreduce the overall width of the headrest. This can also eliminate thepresence of hard plastic structures on the sides of the headrest whichmay pose a visual obstruction to a person seated in a seat including theheadrest as well as persons seated behind the headrest, and, which maypose a hazard (i.e., something for the user's head or another passengershead to crash into) in a collision.

In one aspect, a vehicle headrest includes a main body portion having afront surface arranged to support a back of a head of a user. The mainbody portion includes first and second speakers which are disposedwithin the main body portion, and a cushion layer that is configured tosurround the speakers and provide cushioning for a user's head. Thecushion layer includes acoustic channels for controlling a radiationpattern of acoustic energy radiated from the speakers.

Implementations may include one of the following features, or anycombination thereof.

In some implementations, the cushion layer defines the acousticchannels.

In certain implementations, the cushion layer defines cavities which arelined with an acoustically opaque material to provide the acousticchannels.

In some examples, the vehicle headrest includes acoustic chambers forenclosing back portions of the first and second speakers. The cushionlayer surrounds the first and second speakers and the acoustic chambers.

In certain examples, the main body portion includes a core that isconfigured to support the speakers. The core defines portions of theacoustic chambers for the first and second speakers.

In some cases, the main body portion includes a back cover connected tothe core. The back cover and the core together define the acousticchambers.

In some implementations, the headrest includes one or more support rodsconnected to core.

In certain implementations, the core includes one or more sockets forreceiving the one or more support rods.

In some examples, the cushion layer is configured to engage the core soas to inhibit leakage of acoustic energy between the first and secondspeakers in a region between an outer surface of the core and an innersurface of the cushion layer.

In certain examples, the speakers are arranged so as to direct acousticenergy in diverging directions, relative to each other.

In some cases, the speakers are arranged with firing angle of 15 degreesto 60 degrees.

In certain cases, the first and second speakers are arranged with avertical elevation angle within 5 degrees from horizontal.

In some implementations, the acoustic channels have a vertical spreadangle from the top and bottom of the speaker of 15 degrees to 30degrees.

In certain implementations, the headrest includes grilles oracoustically transparent fabric disposed within the acoustic channels.

In some examples, the grilles are acoustically transparent with 50% orless acoustic occlusion.

In certain examples, a filler material is disposed within the acousticchannels, and the grilles inhibit the filler materials from contactingthe speakers.

In some cases, the filler material is acoustically transparent with 2 dBor less loss in a 100 Hz to 5 kHz frequency band.

In certain cases, the cushion layer is formed of an acoustically opaquematerial.

In some implementations, the main body portion includes a cover layercovering the cushion layer.

In certain implementations, the cover layer covers the acousticchannels, and the cover layer is acoustically transparent at least inthe regions covering the acoustic channels.

In another aspect, a vehicle seat includes a headrest which includes amain body portion having a front surface arranged to support a back of ahead of a user. The main body portion includes first and second speakerswhich are disposed within the main body portion, and a cushion layerthat is configured to surround the speakers and provide cushioning for auser's head. The cushion layer includes acoustic channels forcontrolling a radiation pattern of acoustic energy radiated from thespeakers.

Implementations may include one of the above features, or anycombination thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a perspective view of an inner portion of a prior artheadrest having speakers, showing internal components of the headrest.

FIG. 1B is a perspective view of the prior art headrest of FIG. 1A,showing additional internal components of the headrest.

FIG. 1C is a perspective view of the prior art headrest of FIG. 1A,showing external components of the headrest.

FIG. 2A and 2B are front and back perspective views, respectively, of anvehicle headrest with acoustic channels for integrated speakers.

FIGS. 3A and 3B are front and back perspective views, respectively, of acushion layer from the vehicle headrest of FIGS. 2A and 2B.

FIGS. 4A and 4B are front and back perspective views, respectively, ofthe cushion layer of FIGS. 3A and 3B shown with recessed grilles.

FIGS. 5A and 5B are front and back perspective views, respectively, of acore assembly from the vehicle headrest of FIGS. 2A and 2B.

FIGS. 6A and 6B are front and back exploded perspective views,respectively, of the core assembly of FIGS. 5A and 5B.

FIGS. 7A, 7B, and 7C are front elevation, top cross-sectional, and sideviews, respectively, of the vehicle headrest of FIGS. 2A and 2B shownwith a user's head.

FIG. 8 is a top cross-sectional view of another implementation of anvehicle headrest with acoustic channels for integrated speakers.

DETAILED DESCRIPTION

Referring to FIGS. 2A and 2B, an exemplary vehicle headrest 200 includesa main body portion 202 for supporting the back of a user's head; andone or more (two shown) support rods 204 for detachably mounting theheadrest 200 to a seat back.

The main body portion 202 includes a core assembly 206 which houses aplurality of speakers (e.g., left and right speakers 208 a, 208 b,referenced collectively as “208” (see, e.g., FIGS. 5A and 5B). The coreassembly 206 is enveloped with a cushion layer 210 which is thenenveloped with a cover layer 212. In the completed assembly, thespeakers 208 are entirely enclosed within the main body portion 202. Thecover layer 212 can, for example, be a type of fabric capable of beingdrawn around the core assembly 206 and cushion layer 210.

In certain implementations, the main body portion 202 can have a width wof about 7.9 inches to about 11.4 inches (e.g., 8.5 inches to 9.6inches); a height h of about 5.1 inches to about 9.1 inches (e.g., 7.5inches to 9.1 inches); and a depth d of about 4.3 inches to about 7.5inches (e.g., 4.9 inches to 7.5 inches).

The width w is the dimension measured at the widest point between theright side 214 of the main body portion 202 and the left side 216 of themain body portion 202. The right side 214 of the main body portion 202is the side that is positioned toward the user's right hand side duringnormal, intended use. The left side 216 of the main body portion 202 isthe side that is positioned toward the user's left hand side duringnormal, intended use.

The height his the dimension measured at the widest point between thetop 218 of the main body portion 202 and the bottom 220 of the main bodyportion 202. References to top and bottom are made with respect to theorientation of the headrest 200 during normal, intended use.

The depth d is the dimension measured at the widest point between thefront and back surfaces 222, 224 of the main body portion 202. The frontsurface 222 of the main body portion 202 is the surface against whichthe back of a user's head rests during normal, intended use. The back(rear) surface 224 of the main body portion 202 is the surface oppositethe front surface. The support rods 204 can be metal rods. One or moreof the rods 204 can include a hollow center to serve as a conduit toprovide wires into the core assembly 206 for driving the speakers 208.

The cushion layer 210 can include molded foam (e.g., polyurethane) thatcan be wrapped or assembled around the core assembly 206. It may bedesirable to utilize a cushion material that provides high energyabsorption for cushioning. For example, the cushion layer 210 cancomprise a material having an energy absorption that meets automotivehead restraint safety requirements; in one case safety requirementsdictate that for a spherical mass of 6.8 kg traveling at 24.1 km/h, the3 ms deceleration must not exceed 80 gs. It is also desirable to utilizea cushion material (e.g., a foam material) that provides for highacoustic damping to help acoustically isolate the speakers 208. Thecover layer 212 (e.g., a fabric cover) can then be pulled over thecushion layer 210 to hold the cushion layer 210 tightly against the coreassembly 206 such that the cover layer 212 assume the contours of thecushion layer 210.

Referring to FIGS. 3A and 3B, the cushion layer 210 defines acousticchannels 300 for directing acoustic energy radiated from the speakers208 (items 208 a, 208 b of FIG. 5A and 5B).

The cushion layer 210 may consist of a unitary molded part that isformed to fit over the core assembly 206. The cushion layer 210 mayinclude one or more seams which allow the cushion layer 210 to be fitted(e.g., wrapped) over the core assembly 206. The seams may includeinterlocking features (e.g., tongue-and-groove features) which mate whenassembled. The cushion layer 210 may be held together at the seams viapressure applied by the cover layer 212 and or via adhesive.

Referring to FIGS. 4A and 4B, grilles 400 may be provided to protect thespeakers 208. The grilles 400 may be recessed within the acousticchannels 300. The acoustic channels 300 may, for example, includerecesses 402 (FIG. 7B) for receiving edges of the grilles 400.Preferably, the grilles 400 have a maximum thickness of 3 mm, and aresubstantially acoustically transparent with 50% maximum occlusion. Insome examples, the grilles 400 may serve as support for a fill material716 (FIG. 7C) that can be placed in the acoustic channels 300. Theacoustically transparent fill material (FIG. 7C) can help to obscure orhide the appearance of the acoustic channels 300 behind the cover layer212, in which case, the cover layer 212 (FIG. 2) would be acousticallytransparent at least in the regions overlying the acoustic channels 300.

Referring to FIGS. 5A and 5B, in the illustrated example, the coreassembly 206 is a two piece design that includes a core 500 and a backcover 502. The core 500 receives and supports the speakers 208 andprovides a rigid structural coupling between the support rods 204. Theback cover 502 is secured to a back surface of the core 500 and assistsin enclosing back portions of the speakers 208 to help provide sealedacoustic chambers 504.

Referring to FIGS. 6A and 6B, the core 500 is the main structuralelement of the headrest 200 and is designed to be exposed to asignificant amount of stress. The core 500 includes ribbing 600 (FIG.6B) to help replicate the structural support that might otherwise beprovided by a U-shaped portion of a traditional headrest support bar.The structural features (e.g., ribs 600) of the core 500, define sideportions of acoustic chambers 504 for the speakers 208. The acousticchambers 504 are sealed off with the back cover 502 which forms a backportion of the acoustic chambers 504. While the illustrated exampleincludes two separate acoustic chambers 504 (one for each speaker), insome implementations, the core 500 may alternatively be configured suchthat plural speakers share a common acoustic chamber. The core 500 alsodefines openings 608 which allow back portions of the speakers 208 to beinserted into the acoustic chambers 504. The core 500 can be formed fromplastic, such as acrylonitrile butadiene styrene (ABS), polycarbonate(PC), or a polyphenylene ether (PPE)+polystyrene (PS) blend, in aninjection molding process.

Each of the speakers 208 includes a diaphragm 602, a drive unit 603(e.g., a voice coil motor) arranged along a rear radiating surface ofthe diaphragm 602, a dust cap 604 arranged centrally along a frontradiating surface of the diaphragm 602, and a speaker frame 606 forsupporting the drive unit 603 and the diaphragm 602. The speaker frames606 mount straight to the core 500 with screws 508 (FIG. 5A). Thespeakers 208 can be 0.75 inch to 3.1 inch diameter speakers. In somecases, the speakers may be arranged in pairs (e.g., pairs of 1 inch to1.6 inch diameter speakers) on left and right sides. In some cases, thespeakers may comprise oval speakers.

In some cases, wiring may be routed into the core 500 through one of thesupport rods 204. Alternatively, wiring might also be routed through athird, center post (not shown) rather than inside the support rods. Insome cases, one or more slots may be formed in the core 500 in order topass electrical wiring into the acoustic chambers 504 for driving thespeakers 208. Such slots can be sealed during assembly.

The core 500 also defines sockets 612 for receiving a distal end portionof one of the support rods 204. The distal end portions of the supportrods 204 are pushed up into the sockets 612. The connection between thesockets 612 and the support rods 204 can be a friction fit.Alternatively or additionally, the sockets 612 and the support rods 204can include interlocking features that help to secure the rods 204within the sockets 612. The sockets 612 are configured to providesufficient structural overlap with the support rods 204 such that impactforces that hit the headrest are transmitted into the bars. Furthermore,while an implementation has been described in which the sockets 612 aredefined by the core 500, in some cases, the sockets 612 may be formedseparately from the core 500 and subsequently secured thereto (e.g., viaadhesive or hardware).

The back cover 502 seals off the back of the core 500 from the left andthe right so as seals off the back of the enclosure to provide twodiscrete, sealed acoustic chambers 504. The back cover 502 can be formedof molded plastic (e.g., polypropylene (PP), or acrylonitrile butadienestyrene (ABS)) and may be heat welded onto the core 500. In some cases,a fill material (e.g., a polyester fill) may be disposed within theacoustic chambers 504 to damp resonance within the chambers 504.

With reference to FIGS. 7A through 7C, the speakers 208 are arrangedsuch that at least a portion of the speakers 208 is disposed directlybehind a user's head 700 when the back of the user's head 700 restsagainst the front surface 222 of the main body portion 202 (such thatthe user is facing directly forward; i.e., no rotation of the user'shead) and is centered left-to-right relative to main body portion 202.In some cases, the speakers 208 are arranged such that at least aportion of the speakers (i.e., at least 25% of the volume of thespeakers 208, e.g., 40%-100% of the speaker volume) is disposed directlybehind a user's head 700 when the back of the user's head rests againstthe front surface of the main body portion 202 and is centered relativeto main body portion 202.

As used herein, “directly behind the user's head” is intended to meannot only behind a plane that is parallel to the back of the user's head,but also in a position that is within the breadth of the user's head andbetween the top of the user's head and the user's chin, such that, whenviewed from the front surface of the main body portion 202 (as in FIG.7A), at least a portion (e.g., a substantial portion) of the speakers208 lays within the footprint of the user's head 700 oriented with theback of the head resting against, and centered with respect to, thefront surface of the main body portion.

For the purposes of this disclosure, the user is assumed to have anaverage adult size head. In that regard, an average adult size head hasa breadth (i.e., the maximum breadth of the head, usually above andbehind the ears) of about 5.2 inches to about 6.5 inches; and a measuredmenton to top of head (i.e., the vertical distance from the tip of thechin (menton) to the level of the top of the head, measured with aheadboard) of about 7.8 inches to about 10.0 inches.

Referring to FIG. 7B, the speakers 208 are arranged such that there is a90 mm to 130 mm spacing (dimension A) from dust cap 604 to dust cap 604.Arranging the speakers 208 inside of the headrest 200 at such a tightspacing can help to eliminate obstructions to visibility, both for theuser and for a passenger seated behind the user.

The speakers 208 are arranged to direct acoustic energy from their frontradiating surfaces in diverging directions relative to one another. Thatis, the speakers 208 are each configured to radiate acoustic energyalong a respective central axis 702 a, 702 b (which correspond to thedisplacement axes of the diaphragms) and may be positioned such thattheir central axes 702 a, 702 b cross a vertical plane 704 (i.e., avertical plane that bisects the headrest 200 and extends through thefront and back surfaces 222, 224 of the main body portion 202) at apoint behind the front surface 222 of the main body portion 202.

In some cases, the speakers 208 are positioned such that their centralaxes 702 a, 702 b each diverge at an angle (dimension B) of about 30degrees to about 60 degrees (e.g., about 40 to about 45 degrees)relative to the vertical plane 704. In some cases, the speakers 208 andspeaker opening shapes are substantially symmetrical about the verticalplane 704.

Positioning the left and right speaker 208 a, 208 b so as to directacoustic energy in diverging directions relative to one another helps increating a discrete sound coming out of each speaker 208, and helps toensure that the discrete sound coming out of the left speaker 208 a doesnot cross-over to the right ear, and the discrete sound coming out theright speaker 208 b does not cross-over to the left ear.

The speakers 208 are arranged such that the dust caps 604 are recessedfrom an outer surface of a front portion 706 of the cushion layer 210 adistance of 60 mm to 90 mm (dimension C). This provides sufficientspacing to allow for the formation of a shaped acoustic channel 300which creates a radiation pattern to increase the efficiency from leftspeaker to left ear and right speaker to right ear compared to the leftspeaker to right ear and right speaker to left ear, respectively. Eachof the acoustic channels 300 combined with the central axes 702 a, 702 bcreates the desired radiation pattern. In some cases, such as in theillustrated example, the central axes of the acoustic channels 300 donot coincide with the displacement axes of the speaker diaphragms. Forexample, the central axis of the acoustic channels 300 may diverge fromthe displacement axes 702 a, 702 b of the speaker diaphragm. In somecases, the acoustic channels 300 are arranged such that their centralaxes each diverge at an angle, relative to the vertical plane 704, thatis greater than an angle that the displacement axes of the speakerdiaphragms diverge relative to the vertical plane 704.

The front portion 706 of the cushion layer 210 is 180 mm to 220 mm wide(dimension D) and is configured to provide cushioning for a user's headduring normal use. The cushion layer 210 is acoustically absorptive andinhibits acoustic energy from passing through it, which has the effectof creating acoustic sources that are wider. That is, sound is inhibitedfrom passing through the cushion layer 210, so substantially all (e.g.,at least 90%) acoustic energy that is getting to the user has to passthrough the acoustic channels 300 and hook around the front portion 706of the cushion layer 210. This enables a wider sweet spot, which allowsfor a more consistent sound stage. This design can allow a user's headto lean such that the user's left or right ear is positioned at themiddle of the headrest 200 and still hear substantially the sameacoustic image.

The rear edges of the acoustic channels 300 along the sides theheadrests 200 are positioned 40 mm to 70 mm (dimension E) away from theouter surface of the front portion 706. The inner surface 712 of thecushion layer 210 engages outer surfaces of the core assembly 206 toinhibit leakage between the speakers 208.

In some cases, all edges 714 around the second, outer open ends 710 ofthe acoustic channels 300 are rounded (e.g., having a radius of about 10mm). The presence of sharp edges could create diffraction and create asound image that looks like another source. The inclusion of roundededges can reduce the likelihood of diffraction at the edges.

Referring to FIG. 7C, the speakers 208 are arranged with a verticalelevation angle (dimension F) of +/−5 degrees from horizontal.Preferably, the center height (dimension G) of the speakers 208 iswithin 0 mm to 20 mm of the user's ear height when the headrest isproperly adjusted for safety.

The vertical spread angle (dimension H) from the top and bottom of thespeaker circumference should be 15 degrees to 30 degrees for achieving atapered shape. Acoustically transparent fill material 716, when used,within the acoustic channels 300 should be supported, e.g., by recessedgrilles 400, to prevent interference at maximum cone excursion. The fillmaterial 716 is acoustically transparent with 2 dB maximum loss in the100 Hz to 5 kHz frequency range.

Other Implementations

While acoustic channels have been shown which are substantially oval incross-section, acoustic channels with other cross-sectional shapes arepossible. For example, the acoustic channels could alternatively besquare or rectangular in cross-section. In another example, the acousticchannels could be circular in cross-section; for example, the acousticchannels could be frusto-conical in shape.

While implementations have been described in which a cushion layerdefines acoustic channels, other implementations are possible. Forexample, FIG. 10 illustrates an implementation in which the cushionlayer 210 defines cavities 1000 which are lined with an acousticallyopaque (i.e., not acoustically transparent) material 1002 to inhibitacoustic radiation from passing through the cushion layer 210 to providethe acoustic channels 300. This can allow the cushion layer 210 to beformed of an acoustically transparent material that includes cavitiesthat are lined with an acoustically reflective material 1002 (e.g., anacoustically reflective plastic) to provide the acoustic channels 300.The lining material 1002 may be in the form of an insert (e.g., a moldedplastic piece) that is inserted in the cavities 1000 in the cushionlayer 210 or may be overmolded on the surfaces of the cushion layer 210that form the cavities 1000 to provide the acoustic channels 300. Theuse of such a lining material 1002 may also provide added structuralsupport to the headrest 200. In some cases, the lining material 1002 maybe configured to support the grilles 400. In some examples, the grilles400 may be integrally molded with the lining material 1002. Referencenumbers in FIG. 10 refer to correspondingly numbered elements inprevious figures.

While an implementation has been described in which the cushion layer isa unitary construction, the cushion layer may alternative comprise aplurality of foam pieces that are attached (e.g., with an adhesive)together and/or attached (e.g., via an adhesive) to the outer surface ofthe core assembly.

In some cases, the cover layer can include voids in the regions of theacoustic channels and the grilles can be left exposed through the voidsin the cover layer.

Although implementations have been described in which support rods areprovided for attaching a main body portion of a headrest to a seat back,in some cases, the main body portion may be integral with a seat back.

A number of implementations have been described. Nevertheless, it willbe understood that additional modifications may be made withoutdeparting from the scope of the inventive concepts described herein,and, accordingly, other embodiments are within the scope of thefollowing claims.

What is claimed is:
 1. A vehicle headrest comprising: a main bodyportion having a front surface arranged to support a back of a head of auser, the front surface being 180 mm to 220 mm wide, the main bodyportion comprising: a core assembly configured to receive first andsecond speakers such that respective displacement axes of diaphragms ofthe first and second speakers each diverge at an angle of about 15degrees to about 60 degrees relative to a vertical plane; and first andsecond acoustic channels for controlling a radiation pattern of acousticenergy radiated from the speakers, the first and second acousticchannels having respective rear edges that are 40 mm to 70 mm from thefront surface; and
 2. The vehicle headrest of claim 1, wherein the coreassembly comprises a core configured to support the first and secondspeakers, and wherein the core defines portions of the acoustic chambersfor the first and second speakers.
 3. The vehicle headrest of claim 2,wherein the core assembly comprises a back cover connected to the core,and wherein the back cover and the core together define the acousticchambers.
 4. The vehicle headrest of claim 1, further comprising one ormore support rods connected to the main body portion.
 5. The vehicleheadrest of claim 4, wherein the core assembly comprises one or moresockets for receiving the one or more support rods.
 6. The vehicleheadrest of claim 1, wherein the first and second speakers aresubstantially symmetrical about the vertical plane.
 7. The vehicleheadrest of claim 1, wherein a central axis of the first acousticchannels is coincident with the displacement axis of the first speaker.8. The vehicle headrest of claim 7, wherein a central axis of the secondacoustic channel is coincident with the displacement axis of the secondspeaker.
 9. The vehicle headrest of claim 1, wherein the first andsecond speakers are arranged with a vertical elevation angle within 5degrees from horizontal.
 10. The vehicle headrest of claim 1, furthercomprising first and second grilles to protect the first and secondspeakers.
 11. The vehicle headrest of claim 10, wherein the grilles areacoustically transparent with 50% or less acoustic occlusion.
 12. Thevehicle headrest of claim 10, further comprising filler materialdisposed within acoustic channels, wherein the grilles inhibit thefiller material from contacting the speakers.
 13. The vehicle headrestof claim 12, wherein the filler material is acoustically transparentwith 2 dB or less loss in a 100 Hz to 5 kHz frequency band.
 14. A seatcomprising the headrest of claim 1.